This research project aims at developing an ultrasensitive gas chromatographic - mass spectrometric (GC-MS) method for rapid and specific diagnosis of pneumococcal pneumonia, bacterial endocarditis and tuberculosis in man. From previous work, it was indicated that specific products or components of infectious agents are detectable in serum, urine, or tissue samples of patients and experimental animals by GC means. The use of GC-MS system is, therefore, planned to detect and to identify the specific metabolites of streptococcal, pneumococcal and mycobacterial strains in their specific culture media, and in body fludis of the infected hosts. Two specific peaks were present in the cultures of streptococci, in sera of rabbits with experimental endocarditis and in sera of patients with streptococcal endocarditis. In patients with negative blood cultures, streptococcal endocarditis was diagnosed based upon the presence of the two specific peaks. The peaks were not present in control sera and cultures and also with other bacteria examined. Another specific peak was present in all the samples associated with penumococcal infection. Attempts were made to identify these specific peaks by mass spectrometric analysis of the peaks and comparing the fragmentation patterns with those of standard compounds (C4 - C7 sugars, aminosugars, unoric acids, alcohols of sugars) . It seems that the specific peaks are sugars and aminosugar components of bacterial origin. GC-MS patterns of sera and urines from patients from patients with active tuberculosis. Computer technique will be used to analyze large amounts of data for differrential diagnosis of tuberculosis from other bacterial or fungal infectious. Further work along these lines should establish GC-MS method as a useful tool in clinical pathology. BIBLIOGRAPHIC REFERENCE: Mitruka, B.M., H.M. Rawnsley, and D.V. Vadehra, Animals for medical Research: Models for the Study of Human Disease, John Wiley and Sons, Inc., New York, 1976.